The main flash is barry allen. A close second is walley west both are the "fastest man alive." Barrey allen created the speed force when he was struck by lighting That supercharged his body. When it happened the speed force echoed thoughout time. With Wally West the samething happened to him when he went to barrys office and created kid flash.
Barry's fastest is 23e42 times speed of light.Walley West was able to save a city of half a million from a nuke in 100 picoseconds going that fast almost melted his friction proof suit. both of the flashes are in the Justice League americaAbout the flash